Problem: need man pages for main programs

- removed all references to class placement
- documented private option on classes, in project.xml
- added support for public/private main programs <main .../>
- also generate new project header if != class name
- generate man pages for main programs (category 1)
Problem: error in symbol used for 'make code'

Solution: fix this.
Problem: abusing project name as prefix

Some files, like _selftest and _classes, should be using short prefix
not the project name. E.g. mlm vs. malamute.

Solution: allow optional prefix property.

Incidentally: also fix some other errors in generation.
Merge pull request #47 from hintjens/master

Problem: need man pages for main programs