Release v0.7.13

Fixes:

• Fixed message regarding program root #209
• Help find correct tools path by searching for make.py. Related to #215
• Fixed importing inside git tree (non-program) #211
• Download mbed 2.0 SDK tools only if mbed.bld is present #216
• mbed export options now match project.py (just added help for the --options) #200
• mbed help command is an alias to mbed --help #191

Documentation:

• Documentation for mbed deploy #203
• Asymmetric git workflow documentation #126
• Set program default target/toolchain during 'mbed compile' if no defaults are set #207