Fix availability calculation for hourly stats

The bug happens when a check is just started or paused

Refs #197
Newline in the end of file
Change calcul of availability & downtime for hour & day to take paused time & tested time into account
Fix errors on uptime bar : color & duration
Fix errors on uptimeBar
Fix error when a check as a long period of pause
Remove condition on current interval in uptimeBar
Fix enter key action in edit form

Closes #204
Use Buffer.byteLength instead of string length for Content-Length header

This prevents Content-Length mismatches when sending multi-byte characters.

See https://groups.google.com/forum/?fromgroups=#!topic/nodejs/LAxACfj5_KI.
Update ignore file for osx hidden files