Bump version to 0.1.0.5.
Use tabs instead of spaces in pseudo-tag lines.

This is to meet the specification in http://ctags.sourceforge.net/FORMAT,
according to which columns have to be tab-separated.

We already tab-separated normal tag lines, but the pseudo-tag lines
in the header were accidentally separated by spaces.

This fixes problems in some ctags file format parsers
(in my case, Sublime Text's CTags plugin).
Add `hashConfig`.
Fix #21: Introduce cache eviction mechanism.

In order to automatically clean the cache when the configuration is updated.

This naive approach might trigger false positive (cache being evicted
while the change in the configuration does not affect the generated tags
files).