Increased timeout for poltergeist from default 30 to 60 (integration tests were often not passed, because of timeout).
Fixed bug related to adding future expense without any income or expenses (error 500). Fixed #34.
Merge pull request #35 from smt116/34-Error-500-if-user-have-expenses-without-any-income

[#34] Fixed bug related to adding future expense. Increased timeout for poltergeist.