fix bootstrap datepicker

The datepicker was broken, because it flowed off the screen[1]. I updated the bootstrap datepicker to something more recent and made sure that it would calculate it's orientation automatically. The result is that in the same screen the datepicker can be seen easily[2].


1. https://www.evernote.com/shard/s19/sh/03ecaa17-1aec-4ea8-bdbb-e3ca0b49ae15/1ac0de1da28a97eb178bd5b181aa0d92/deep/0/Debian---Rbenv+Rails-(after_i3)--Running-.png

2. https://www.evernote.com/shard/s19/sh/88ddb38b-74d4-41af-8f51-5bf4fb0ab1fb/7971b8e89dd86526b16471391cd62c5b/deep/0/Debian---Rbenv+Rails-(after_i3)--Running-.png