Updated readme and started developer documentation
Added check before storing SRS as EPSG, to make sure that later can be decoded

fixes #274
Merge pull request #244 from volaya/master

Changes to README and first version of dev docs
Revision of CLI commands (fixed some wrong strings) and update of man pages
Added values to output of blame command, with option to switch off this behaviour
Rev-list command now uses [unknown] spaceholder when formatting missing emails and/or names
Merge remote-tracking branch 'origin/pr/275'