tools: ceylon doc and ceylon doc-tool alignment

[tombentley]

ceylon doc and ceylon doc-tool both generate HTML output, but currently there's some duplication going on in their implementation.

• They both have (similar) classes for generating HTML
• They both have code for copying resorces out of the jar into the output directory
• They should both include options for specifying additional CSS and JS to be included in the output documentation.

I'm sure some of this should be shared between the tools.

Also there's a inconsistency in our package naming because the one is in com.redhat.ceylon.ceylondoc while the other is com.redhat.ceylon.tools.help

[thradec]

Tom, please don't do any refactoring until I finish issue #560 and #485, I'm working on it now and merging conflict would be terrible. Thanks.

[tombentley]

No worries, I wasn't going to start this any time soon.

I'd love it if you could work some of your magic on ceylon doc-tool too incidentally.

[FroMage]

Moving to M6