Update getinvolved_index.html

clean-up attempt of donation section
Update getinvolved_donations.html

changed  subnav header from "get involved" to "donate to the project"
Update index.html

changed link from direct link to donations page to link to sponsor & donate
Donor Dan Homerick added
Fix broken link to INSTALL file on GitHub

Needed to be https not http
Removed an unwilling donor
pr#192 done by hand
updated css (needed for 'related bar' in docs
fix broken url
fix for flattr button in firefox
Donor Dimap Sl Felipe Garcia added
removing leftovers after build
Donor Eric Hamilton added
Donor Joern Struwe added
Donor Julius Schröder added
updated text from Alajangi Simhachalam
Donor Francis Harvey added
Donor Alain Brunon added
Donor John Mcguire added
Donor Katie Peek added