append functions are not prototype methods
fix HTML capitalization in Highlight2HTML

To be consistent with surrounding code, where we always capitalize acronyms that appear in class names.
avoid loading preprocessors twice

in TemplateExporter

also cleaned up some of the related code.
call append_text from append_map
Add failing tests for tuple unpacking assignments from system cmds
Improve assignment regex to match more tuple unpacking syntax

Closes gh-5305
Merge pull request #5295 from minrk/no-append-prototype

OutputArea.append_type functions are not prototype methods
Merge pull request #5308 from minrk/HTML

fix HTML capitalization in Highlight2HTML
Add some tests for assignment from system/magic commands
Merge pull request #5313 from minrk/double-init-preprocessor

avoid loading preprocessors twice
add NotebookNotary to NotebookApp's class list

adds it to help output and config files
Make Notary.secret_file configurable
Merge pull request #5325 from minrk/notary-config

add NotebookNotary to NotebookApp's class list
Merge pull request #5321 from takluyver/i5305

Improve assignment regex to match more tuple unpacking syntax