As also suggested on
[stackexchange](http://tex.stackexchange.com/questions/112526/errors-wit
h-makeuppercase-and-beamers-insertsectionhead) the new implementation
patches `\sectionentry`, `\beamer@section` and `\beamer@@frametitle`
instead of expanding them.
In the process I also added three more hooks:
- `mthemesectiontitleformat`
- `mthemeframetitleformat`
- `mthemeplaintitleformat`
So the user can change the behavior of each element independently. As
default the new formats are dependent on `mthemetitleformat`.
For testing purposes I integrated @elliottd s frames from this PR #94
This should fix the `allowframebreaks` issue for real now.
The `mtheme` is compatible with other colour themes and (technically) other font themes. Moving these declarations to the .tex file makes it easier for the user to use a custom colour theme or to compile the slides on a computer without Fira Sans.
Although syntax highlighting is nice, `minted` is a nonessential dependency that greatly complicates compilation for new users. Since using the `mtheme` does not require you to install Pygments or use `--shell-escape`, the demo slides should not either.