Adds git hash to compiler's version switch. Refs #1119.
Fixed parsing of float literals.

Float literals were not parsed properly when their fractional part
exceeded 53 significant bits. This affected in particular math.PI
and math.E. Rather than reinventing the wheel, this patch reuses
C's strtod() implementation, which already does the heavy lifting
with respect to correctness, though some caution is necessary to
keep float parsing locale-independent.
Add support for structs/unions defined in structs/unions
Added test for anonymous structs and unions
Removed time and added a hash based on filename, line and column for creating a unique struct id
More human readable `$`(float)

The output matches that of Python (eg 1e100, not 1.0e100), but also
reflects locale (assuming it was set using setlocale() before).
Tests for `$`(float)
Fixing issue #1090
Sorting enumerations and generation of consts for enumfields with the same value + test
Fixed #1090
Made the code more robust and detect nkPrefix as number (-1 or +4) for enum sorting. Added also a new test for enums.
Forces babel package descriptions to end with a dot.
Hyperlinks together importc like pragmas.
Starts backends.txt with bits from nimrodc.txt.
Hyperlinks back JavaScript target.
Starts nimrod calling backend section.
Adds nimrod to backend examples.
Adds examples of backend calling nimrod.
Mentions memory management.
Adds tidbit about threads.