Extendibility in format-tags & localized Stay-Alert

Added possibility to extend with custom inline-formatting-tags (i.e. <code></code>) by wrapping them around the selection and executing "insertHTML" command.

Additionally: possibility to pass the stay-alert text via options
Added Icon for wrapping a <code>-Tag
Reset for Icons

...to avoid conflicts with other ".icon"-classes (like used by Bootstrap)
Linking allows anchors and relative paths

Linking made more flexible: now it allows anchors and relative paths without converting it to absolute ones - useful for further migration.
Linking extended by recognition of eMail-addresses

When typing in an email-address, it prepends "mailto:" instead of "http://"
Fixed Merge-Issue
Fixed Merge-Issue #2
Fixed Merge-Issue #3
Fixed Merge-Issue #4
Fixed Merge-Issue #5
Fixed Merge-Issue #6
Fixed Merge-Issue #7
Merge pull request #91 from brainedia/master

Extendibility in format-tags & localized Stay-Alert