Rewrite of different stuff

[bueltge]

At first, sorry for this request without commits for each step, change. 😇
I wrote on different thinks there the users need. However I think this changes are really helpful for others and I think also that this changes have no problems on current installs.

• Add settings page, there also save, change values. should fixed Wrong form action value #14
• Rewrite of settings default, so that is easier to save it.
• Add function to save settings without redundant source.
• Clean up stylesheets for scrum overview.
• Each Issue on the Scrum Board use his status color to more illustrate.
• Fix different source topics.
• Add Status view, each first string of the status, to the issue.
• Add screenshot, should fixed screenshot for README  #17
• Enhance readme
• Should be fixed Add the ability to click on a card to edit the issue #11 ; small enhancements in a issue, edit is possible via click on the ID of a issue

I tested only in MantisBT 1.2*, not for 1.3* or 2.*!

[luzpaz]

I tested only in MantisBT 1.2*, not for 1.3* or 2.*!

1.2 is way obsolete, just sayin.

[bueltge]

@luzpaz You have right. It should we also work in 1.3, the difference should be only the require of the api - https://github.com/mantisbt-plugins/scrum/blob/master/Scrum/pages/board.php#L6 to require_api(), but this function is not usable in 1.2*