Fixed mapping for r
Add copyright notice to files
Updated README
Added varnam_is_known_word

This function checks if the supplied word is known to varnam
Standardizing learnings file path created by varnamc

$HOME/.varnam/suggestions -> If no out directory is specified
out_dir/suggestions -> If out directory is specified
Added varnam_init_from_lang

This allows varnam to be initialized by specifying the language code.
Helper methods to get scheme file and suggestions file
learned_on will be stored as a unix timestamp in localtime
API to set suggestions and symbols directories
Updated varnamc to use the new varnam_init_from_lang
Introducing flags to symbol table

Flags is a bit field which can be used for keeping additional
information about the symbol.

Making a prefix tree after VST file compilation, so that
can_find_more_matches can work faster rather than issuing a LIKE query
which will not use an index
Optimizing can_find_more_matches using prefix tree

This made learn 2 times faster
Caching last learned word and it's if to improve vwt_get_word_id
Removing learnings file compacting as it was impacting the performance
Caching vst_tokenize so that repeated tokenization will be improved

From this commit, any tokens that is created will be cached. This avoid
looking up for the same token again and again each time. This also
improves the performance drastically by 50%.
Fixing segfault in the cache

segfault was happening because vst_tokenize will give cached result and
noise reduction will remove a value from this array causing a change in
the cached value.

This commit copies the cached content to avoid the issue
added travis.yml