Report Output Enhancements
Fixing previous pull request

- 'default' wasn't being set as a string
- changed all references to '#{ARGV[0] || DefaultDb}' to just DefaultDb
Cleaning up trailing whitespace
README.md: explain config menu
version: bump to 1.2.2
fetch_git_commits: fix bug

When passing from and to variables for dates, the to_s was rendering
them most of the time alright. On some cases however, this fed git
some weird strings for dates, and raised some problems. Making sure
that a proper format is passed with strftime was the solution.
invoice_ui: robustness fix

Only fetch git commits IF the user has set a git repo
Merge branch 'nnadboralski-GH33_report_output_enhancements'