parsing of user defined type classes
Removed outdated bootstrapping info from install.txt
fix parsing of ``proc foo(x: distinct Type)``
working code for simple cases of user-defined type classes
prevent eval crashes due to PContext-dependent ops not being available in evalConstExpr
Implemented ability to connect through proxies for the httpclient module.
implemented delegators and improved the error messages of unmatched type classes
fix tnoop

This commit requires further investigation.

Fixing semExpr(nkCall) once and for all to work with sym-choices and to
allow overloading with immediate templates and macros will probably set
this straight too.
proper discrimination between csEmpty and csNoMatch

fixes twrongtupleaccess and topaque
fix tcompiles
fix tisop

Adding nil checks on the exit paths for semCompiles errors.
This was probably not needed before, because semIndirectOp
had a special detection for semCompiles contexts. We could
try to restore these, but wouldn't this just postpone the crashes
until someone tries the same expressions in nimrod check?

One of the previous commits also used errorNode to avoid
returning nil. This may be an alaternative approach.
minor improvement towards tgenericshardcases
docgen: more newlines in the output to support primitive postprocessors
bugfix: 'not x of y' requires ()
float64 is now an alias to 'float'; fixes #545
fixes #572
Merge branch 'master' of github.com:Araq/Nimrod
tester compiles again
conversions to float32 are allowed again but of lower priority
bugfix: conversions to float32 are allowed again but of lower priority