More minor improvements to README to help polish the 0.2.0 release:
- Add note about Ubuntu 8.04 (in lieu of starting a README.Linux file).
- Fix introductory paragraph to Bulding OpenOCD
- Remove some vestigial texinfo markup.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2448 b42882b7-edfa-0310-969c-e2dbd0fdcd60