Switch build system to mesonbuild.

There is no more integrated build of dependencies in the build system.
Dependencies are discovered using pkg-config except for ctpp2 where there
is no pkg-config file.

include/meson.build

@@ -0,0 +1,31 @@
+headers = [
+  'indexer.h',
+  'library.h',
+  'manager.h',
+  'reader.h',
+  'searcher.h'
+]
+
+if xapian_dep.found()
+  headers += ['xapianIndexer.h', 'xapianSearcher.h']
+endif
+
+install_headers(headers, subdir:'kiwix')
+
+install_headers(
+  'common/base64.h',
+  'common/networkTools.h',
+  'common/otherTools.h',
+  'common/pathTools.h',
+  'common/regexTools.h',
+  'common/resourceTools.h',
+  'common/stringTools.h',
+  'common/tree.h',
+  subdir:'kiwix/common'
+)
+
+
+install_headers(
+  'ctpp2/CTPP2VMStringLoader.hpp',
+  subdir:'kiwix/ctpp2'
+)