readme: add how to: git branching model
readme: becoming a Collaborator
Add modified markdown logo from https://github.com/dcurtis/markdown-mark
Tiny rename to Mage Markdown due to Magento Connect guidelines
Replace MD with [M↓]
[FEATURE] Live preview of rendered markdown (not MD Extra) in editor elements. Preview will be shown below the textarea field and updated via keyup event with an automatic scrolling to the current position.
[FEATURE] Live preview of rendered markdown (not MD Extra) in editor elements. Preview will
be shown below the textarea field and updated via keyup event. The preview box can be
resized by clicking on it, 2nd click puts it back to default height. Hidden Live-Scrolling
feature: If you scroll to position x in the preview box and you edit the same position in the
textarea you will have the preview box updated with your current text without scrolling.
[FEATURE] Markdown Extra can be enabled or disabled only for transactional emails.
Add interface SchumacherFM_Markdown_Model_Markdown_Interface if you want to
implement your own MD parser.
Merge develop branch into master for version 1.4.0

* develop:
  [FEATURE] Markdown Extra can be enabled or disabled only for transactional emails. Add interface SchumacherFM_Markdown_Model_Markdown_Interface if you want to implement your own MD parser.
  [FEATURE] Live preview of rendered markdown (not MD Extra) in editor elements. Preview will be shown below the textarea field and updated via keyup event. The preview box can be resized by clicking on it, 2nd click puts it back to default height. Hidden Live-Scrolling feature: If you scroll to position x in the preview box and you edit the same position in the textarea you will have the preview box updated with your current text without scrolling.
  [FEATURE] Live preview of rendered markdown (not MD Extra) in editor elements. Preview will be shown below the textarea field and updated via keyup event with an automatic scrolling to the current position.
  Replace MD with [M↓]
  Add modified markdown logo from https://github.com/dcurtis/markdown-mark Tiny rename to Mage Markdown due to Magento Connect guidelines
  readme: becoming a Collaborator
  readme: add how to: git branching model