Merge branch 'release/v0.2.0' into develop
icon engine plugin for font awesome

Added icon engine plugin which provides icons from the Font Awesome (http://fontawesome.io/)
Add a few icons to the main menu
Several new actions in edit menu

* add several new actions to edit menu: Cut, Copy, Paste, Format Strong, Format Emphasize
* new class MarkdownManipulator which is responsible for manipulating the markdown text document
Merge branch 'feature/font-awesome' into develop
Some more icons in main menu
Refactor MarkdownEditor

move increase/decrease heading level code from MarkdownEditor to MarkdownManipulator
Print support

added support for printing the markdown document.

closes issue #18
set default style on application start
Add support for several new icons to FontAwesomeIconEngine
Add icon and shortcut to print action
New format actions

add two new format actions (inline code and strikethrough) to the edit
menu.
Use markdown.css as default style
Fix warnings
Synchronize scrollbars

Synchronize vertical scrollbars of markdown editor and live preview.
prevent UI block after copy&paste

when big text parts are inserted per copy&paste, the UI could block
because of MarkdownHighlighter::highlightBlock() call "storm".

this change prevents the blocking by checking if the document actually
changed since the last call. But now we have to reset this previousText
variable when we load a file or use the "new" action.
Reset highlighter when styles changes
Support math expressions

Support rendering of math expressions (LaTeX, MathML) using MathJax javascript
library.
Disk cache for webview

Add disk cache to improve performance of webview when
accessing remote content
Add template.html to project