Use correct grammar for error message.

When the number of parameters is 1, then 'parameter' should remain singular.
Otherwise pluralize it.
Use backticks for the unsafe keyword in error messages
Attempt to fix x86 only strconv test failure
auto merge of #6026 : isanbard/rust/ca73fbf72615575f106ee18160580711aca89d85, r=catamorphism

When the number of parameters is 1, then 'parameter' should remain singular.
Otherwise pluralize it.
auto merge of #6027 : alexcrichton/rust/more-backticks, r=catamorphism

It seems that the general convention of error messages is to have keywords in backticks, so it's probably a good idea to keep doing that.
core, rustc: Warning police
rustc: Comments only: change XXX to FIXME
rustc: Remove dead code
auto merge of #6022 : catamorphism/rust/warning-police, r=catamorphism
inline the primitive numeric operations
auto merge of #6028 : Kimundi/rust/strconv-test-fixup, r=brson

r? @brson 

Can't test atm, but it probably failed because of 32bit float precision loss of the float literal.
auto merge of #6034 : thestinger/rust/num, r=catamorphism,pcwalton
Fix issue #5976 - HANDLE leaks and undefined/bad behavour
on windows.
Remove os::waitpid because:
 - The return value meant different things on different
   platforms (on windows, it was the exit code, on unix it was
   the status information returned from waitpid).
 - It was undocumented.
 - There also exists run::waitpid, which does much the same
   thing but has a more consistent return value and also some
   documentation.
Oops, the should_fail test needs to be ignored on windows.
Cleanup some mistakes made during rebasing/merging.
auto merge of #6010 : Dretch/rust/run-windows, r=brson

This fixes #5976.

It also removes `os::waitpid` in favour of (the existing) `run::waitpid`. I included this change because I figured it is kind of related.

r?
Improve the unused unsafe block warning to include unsafe blocks in unsafe functions
Removing more unnecessary unsafe blocks throughout
Fixing some various warnings about unused imports