#35 help system integration

[Jack D. Unrue]

GF should facilitate help system integration. This has
several facets:

- which help systems to support? WinHelp is deprecated
but several apps still use it. HtmlHelp/CHM format is
the most popular. Rumor has it that Vista introduces a
completely new format.

- enable context-sensitive help topics and event processing

- invoke help system viewer

- i18n compliance