'Fix' for Ninja generator in Windows

Reference: http://www.cmake.org/Bug/view.php?id=15278
Until the bug is fixed in cmake, the generated files need to be fixed by
running 'sed' to replace '\' with '/'
Only 'fix' ninja in Windows

Also add a comment explaining the issue.
make it possible to pass options to the build tool; add help for that
remove non-ascii char
Merge pull request #84 from bogdanm/fix-ninja

'Fix' ninja build files on Windows
Merge pull request #83 from autopulated/parallel-build

make it possible to pass options to the build tool; add help for that
centralise source URL/spec parsing
update other subcommands for api change
Merge branch 'master' of github.com:armmbed/yotta into branch-depend
fix link
Support depending on branches of git repos.

To do this we fetch all remote branches when cloning, which probably isn't the
best thing to do. Instead it'd be better to fetch the minimum we need to list
remote tags and branches, and then pull a specific remote tag or branch into
the final installation dir.
support pulling head from github branches
don't break when there's no access token in URL
Merge pull request #85 from autopulated/branch-depend

Make it possible to specify branches as dependencies.
Try to improve the readme
bump version
use SPDX identifier for license in setup.py
use approved classifier for license
Update readme.md
fail gracefully if the user doesn't have access to the github repo requested; fix build with branch dependencies