Move the templating system to mustache instead of ctpp2.

Mustache templating system is a bit simpler than ctpp2 and ctpp2 is no
more maintained (see #189).
We are moving to the kainjow's Mustache project
(https://github.com/kainjow/Mustache).

It simplify a lot our system has it is header only and we don't have to
precompile the template.

Fix #21

meson.build

@@ -4,7 +4,6 @@ project('kiwix-lib', 'cpp',
   default_options : ['c_std=c11', 'cpp_std=c++11', 'werror=true'])
 
 compiler = meson.get_compiler('cpp')
-find_library_in_compiler = meson.version().version_compare('>=0.31.0')
 
 static_deps = get_option('android') or get_option('default_library') == 'static'
 if get_option('android')
@@ -19,81 +18,22 @@ libzim_dep = dependency('libzim', version : '>=4.0.0', static:static_deps)
 pugixml_dep = dependency('pugixml', static:static_deps)
 libcurl_dep = dependency('libcurl', static:static_deps)
 
+if not compiler.has_header('mustache.hpp')
+  error('Cannot found header mustache.hpp')
+endif
+
 extra_cflags = ''
 if target_machine.system() == 'windows' and static_deps
   add_project_arguments('-DCURL_STATICLIB', language : 'cpp')
   extra_cflags += '-DCURL_STATICLIB'
 endif
 
-
-
-ctpp2_include_path = ''
-has_ctpp2_dep = false
-ctpp2_prefix_install = get_option('ctpp2-install-prefix')
-ctpp2_link_args = []
-if ctpp2_prefix_install == ''
-  if compiler.has_header('ctpp2/CTPP2Logger.hpp')
-    if find_library_in_compiler
-      ctpp2_lib = compiler.find_library('ctpp2')
-    else
-      ctpp2_lib = find_library('ctpp2')
-    endif
-    ctpp2_link_args = ['-lctpp2']
-    if meson.is_cross_build() and host_machine.system() == 'windows'
-      if find_library_in_compiler
-        iconv_lib = compiler.find_library('iconv', required:false)
-      else
-        iconv_lib = find_library('iconv', required:false)
-      endif
-      if iconv_lib.found()
-        ctpp2_link_args += ['-liconv']
-      endif
-    endif
-    has_ctpp2_dep = true
-    ctpp2_dep = declare_dependency(link_args:ctpp2_link_args)
-  else
-    message('ctpp2/CTPP2Logger.hpp not found. Compiling without CTPP2 support')
-  endif
-else
-  if not find_library_in_compiler
-    error('For custom ctpp2_prefix_install you need a meson version >=0.31.0')
-  endif
-  ctpp2_include_path = ctpp2_prefix_install + '/include'
-  ctpp2_include_args = ['-I'+ctpp2_include_path]
-  if compiler.has_header('ctpp2/CTPP2Logger.hpp', args:ctpp2_include_args)
-    ctpp2_include_dir = include_directories(ctpp2_include_path, is_system:true)
-    ctpp2_lib_path = join_paths(ctpp2_prefix_install, get_option('libdir'))
-    message(ctpp2_lib_path)
-    ctpp2_lib = compiler.find_library('ctpp2', dirs:ctpp2_lib_path, required:false)
-    if not ctpp2_lib.found()
-      ctpp2_lib_path = join_paths(ctpp2_prefix_install, 'lib')
-      message(ctpp2_lib_path)
-      ctpp2_lib = compiler.find_library('ctpp2', dirs:ctpp2_lib_path)
-    endif
-    ctpp2_link_args = ['-L'+ctpp2_lib_path, '-lctpp2']
-    if meson.is_cross_build() and host_machine.system() == 'windows'
-      iconv_lib = compiler.find_library('iconv', required:false)
-      if iconv_lib.found()
-        ctpp2_link_args += ['-liconv']
-      endif
-    endif
-    has_ctpp2_dep = true
-    ctpp2_dep = declare_dependency(include_directories:ctpp2_include_dir, link_args:ctpp2_link_args)
-  else
-    message('ctpp2/CTPP2Logger.hpp not found. Compiling without CTPP2 support')
-  endif
-endif
-
 all_deps = [thread_dep, libicu_dep, libzim_dep, pugixml_dep, libcurl_dep]
-if has_ctpp2_dep
-  all_deps += [ctpp2_dep]
-endif
 
 inc = include_directories('include')
 
 conf = configuration_data()
 conf.set('VERSION', '"@0@"'.format(meson.project_version()))
-conf.set('ENABLE_CTPP2', has_ctpp2_dep)
 
 if build_machine.system() == 'windows'
      extra_link_args = ['-lshlwapi', '-lwinmm']
@@ -109,13 +49,6 @@ subdir('test')
 
 pkg_requires = ['libzim', 'icu-i18n', 'pugixml', 'libcurl']
 
-if has_ctpp2_dep
-  extra_libs += ctpp2_link_args
-  if ctpp2_include_path != ''
-    extra_cflags = ' -I'+ctpp2_include_path
-  endif
-endif
-
 pkg_conf = configuration_data()
 pkg_conf.set('prefix', get_option('prefix'))
 pkg_conf.set('requires', ' '.join(pkg_requires))