Bump version to 0.73

Updating CHANGELOG, setting version in Info.plist.

Fix typo in changelog.

Fixing some changelog typos; correcting name of OS X 10.11

Switching master to 64-bit branch

Version 0.7 (beta 1): 64-bit

Adjusting bundle to reflect beta status in version number

Merge branch '64-bit-support' of github.com:snark/jumpcut into 64-bit…

…-support