Ran 2to3
Fix Python3 problem after conversion

- yokadi can be launched
- unit test state is ok
Fix Python3 stuff after merging
Update python version in README file
Update gitignore
Update travis to build against python 3.4
Fix file usage
Fix suffix am|pm

indeed if user is using 17m we raise an exception instead of displaying an error message (format problem)
Close file handle
Explicitly use python3 as an interpreter name
Fix crash in `help n_list`
Merge pull request #1 from agateau/python3-sqla

Python3 sqla
When a task is removed, delete matching rows in TaskKeyword
When a project is removed, delete matching rows in ProjectKeyword
Delete tasks when a project is deleted at the db level
Delete matching rows in Recurrence when a task is removed
Delete any pending TaskLock when a task is removed
Fix on python 3.2

remove u before string
Remove usage of list when not needed
Remove >=1 when we can use > 0