Document how insignificant parameters work

 * Document how two Tasks with the same params are identical
 * Document how significant=False changes the signature
Merge pull request #262 from onlynone/master

Document how insignificant parameters work
Merge pull request #264 from daleroberts/master

Fix incorrect hadoop stat msg match
bumped version to 1.0.13 and uploaded to pypi
Add missing information about the first example in README.md
Clean up example: use context manager when opening files (already done elsewhere in the file), use  rather than %s, remove trailing spaces on a number of lines, break lines at under 80 characters
Merge pull request #269 from jeffknupp/master

Add missing information about the first example in README.md; clean up example code