fixes for wrong % '%e' formatting

borrowed tests form cpython stdlib
added tests from cp28936
fixed NAN and INF case for % '%E','%F' and '%G' formatting
fixed missing -0.0 in case of % '%e' formatting
simplified % '%e' formatting - removed dead code/checks
fixed % '%g' formatting for precision 0 and 1
adjusted comment
cleanup before PR

restored 'f' checks for trailing zero
removed confusing comment
merged copy/paste function
changes as requested in PR feedback
Modified PythonBinary:Read if size to read is zero return empty string
Merge remote-tracking branch 'paweljasinski/cp28936' into ipy-2.7-maint
Merge remote-tracking branch 'fdanny/socket_updates' into ipy-2.7-maint
Add prefix\Lib to sys.path instead of sys.prefix.
Add an -X:Attach option to immediately attach a debugger.

Only available in DEBUG builds, obviously