plenty changes for 2.0
use NaN for empty cache size
make sure tests have close to 100% coverage
optimize cache searching
dict.items is not generator in python2.x
we also tested against Python 3.4
bugfix when inserting empty document
Rewrote Documentation
Removed Limitiations from README

Limitations are described in the docs
Switched to squared badges in README
add testcase and comments
optimize insert_multiple
Revert "optimize insert_multiple"

This reverts commit 0d0d77edc26c88934a52cf88fb4b4447686ad00d.
Merge branch 'master' into 2.0
Merge branch '2.0' of https://github.com/eugene-eeo/tinydb into eugene-eeo-2.0

Conflicts:
	README.rst
	tinydb/middlewares.py
Merge branch 'eugene-eeo-2.0'
Fix a typo in the build status link
Better support for IDs (see #17)
Fixed code coverage
Removed debug output