Documents account HTML clients
Improves configuration documentation of the account history
Improves compatibility with xampp environments
Adds documentation for HTML client configuration options
Adds div container for better styling possibilities
Retrieves mime types by PHP methods to improve compatiblity to xampp environments
Sends errors in case of exceptions to the frontend
Displays errors if upload fails
Fixes media item initialization for new items
Revert "Adds div container for better styling possibilities"

This reverts commit 5b0379b98f1d5b4d11118b6dc37c4f2f36d99423.
Revert "Adds div container for better styling possibilities"

This reverts commit 5b0379b98f1d5b4d11118b6dc37c4f2f36d99423.
Merge pull request #578 from nsendetzky/2014-04-06_upload

Improves compatibility with Windows XAMPP environments and displays errors if upload in admin interface fails
Merge branch 'master' of https://github.com/Arcavias/arcavias-core
Uses centered default image for upload area in admin interface
Merge pull request #576 from nsendetzky/master

Uses centered default image for upload area in admin interface
Separates overview list into one list page per domain
Merge pull request #579 from nsendetzky/master

Separates overview list into one list page per domain
Documents account HTML clients
Improves configuration documentation of the account history
Adds documentation for HTML client configuration options