Extract title from .title[my title]

[arnfinn]

Previously the HTML title was extracted from the first
occurrence of #. Thus, the HTML title was the title of
my second slide if I used .title for the first slide.

Please modify this pull request as you like:)

[robertodr]

Thanks! Do the test pass locally?

[bast]

Thanks! The broken test is "my" fault. This works locally but for some weird reason not on Travis. I need to redesign that test.

[bast]

I need to think a bit about this change. Background: the .title[] is a custom extension that we have defined. I am considering moving extensions to user space so that you can define them along your project and in this repo serve only vanilla render engines (currently remarkjs but I would also like to add reveal). It is a reasonable change in the current setting but please let me sleep on it ...

[arnfinn]

No problem @bast :)

[bast]

I will meditate over night and revisit this tomorrow and probably merge :-) Thanks a lot for contributing to this code!

[bast]

Merged. I think it makes sense in the current setup which might change in future but that's another story. Thanks again.