"From time" cannot be later than "To time" and hours cannot be negative
Changed contact_date to Datetime so appointment or call with time can be scheduled
Update time_log.py
removed unecessary backslash
Merge branch 'develop' of https://github.com/revant/erpnext into develop
Merge pull request #2451 from revant/develop

"From time" cannot be later than "To time" and hours cannot be negative