Bump to 3.1.0.rc1. Please report any bugs
Improved performance with counter_cache for tags (tag.taggings_count), taken from https://github.com/lichtamberg/acts-as-taggable-on/commit/52836c54d9abf1cc77be4df7b4c61cea90869c50
Memoize cache columns more with more specific name
Adjust Tagging to only add counter cache when available.

Failing test demonstrates counter cache not added when column absent.
Confirm counter cache is enabled when caching column added

This ensures the code is backwards compatible if the migration is not
run.
Update CHANGELOG to reflect no breaking changes
Check for #390 to prevent application breakage.
Improved performance with counter_cache for tags (tag.taggings_count), taken from https://github.com/lichtamberg/acts-as-taggable-on/commit/52836c54d9abf1cc77be4df7b4c61cea90869c50
Adjust Tagging to only add counter cache when available.

Failing test demonstrates counter cache not added when column absent.
Confirm counter cache is enabled when caching column added

This ensures the code is backwards compatible if the migration is not
run.
Update CHANGELOG to reflect no breaking changes
Bump to 3.1.0.rc1. Please report any bugs
Added Rubinius and ruby 2.1.1 to travis
Merge remote-tracking branch 'origin/dgilperez-counter_cache' into dgilperez-counter_cache

Conflicts:
	lib/acts_as_taggable_on/tagging.rb