fix for FB #4763, refactorings in AzureVM and AzureOSImage to replace xml string builder with serialzation
Revert "fix for FB #4763, refactorings in AzureVM and AzureOSImage to replace xml string builder with serialzation"

This reverts commit dae6f57736ffa78ba0dcbe3b509b750635a68f88.
add http proxy support via System properties
rename get proxy config data method
update http proxy parameter names
Merge pull request #92 from vladmunthiu/2014.08

http proxy support via System properties