Improve output processing and readme

Only output plugin comments if there's content to display

Also, more readme improvements

See merge request !5

Also, more readme improvements

Readme updates for v0.2



See merge request !4

Bump version for recent changes



See merge request !3

Support for additional HeadSpace2 features

Enables custom JS and CSS includes, along with raw header and footer content.

Custom page title rewriting is also added. Pre 4.1 (`title-tag`) support is tentative and likely needs more testing.

See merge request !2

Basic support

Initial plugin functionality, which supports the keywords I actively used. It _does not_ support all HeadSpace2 data because I used so few of the features.

See merge request !1