Issue when compiling on windows with path containing white space

[jmchiappa]

Compilation failed on Windows 7 x64. I'm using the release 1.2.0.
It appears when the build path contains white space.
By modifying platform.txt file in this way
compiler.extra_flags=-mcpu={build.mcu} -mthumb "@{build.opt.path}"
It fixed the issue. I just added double quote.

[fpistm]

Thanks for the report and fix @jmchiappa