improved behavior of '-p' option.
supported indexing to enum declarations.
added a test for "-g" option.
added verbose option "-v".  changed the switch to enable "guess mode" "-g" to "-G".
updated test for "-G" option.
define file_index.db as a constant.
added wrapper scripts.
updated Makefile
added "lazy mode" which assumed index of header files are always the
same as far as in the same project. This is not always true but almost
always true. This option is enabled by specifying "-l" option.
Merge branch 'devel' of https://github.com/katonori/cxxtags into devel
updated wrapper scripts. skip indexing when option "-MM" is specified.
changed argument parser to pass through the option "-D" to cxxtags_core.
changed the wrapper scripts to be able to specify exclude list by the environment variable.
added a cmake file.
added an utility function.
added wrapper scripts.
cleanup Makefile.
added an option "-E" this option invokes "empty mode".
added a separate database mode.
removed obsolete scripts.
stopped unneeded outputs.