Added cellular modem libs to sync script
Added missing constructor for CDMA modem initializer
Added CellularModem as an abstract base class for modem implementations

Now both UbloxUSBGSMModem and UbloxUSBCDMAModem inherit from
CellularModem.
Updated tests

- Vodafone tests are gone for now
- Added u-blox TCP test (UB_1) and SMS test (UB_2).
- tests can now have more than a single source directory
Added command line source/build directory option
Added u-blox test repository

Also, allow a repository to synchronize with more than one source
directory.
Changed u-blox modem test

The test is not automated now, so it can be synced with the official
repository.
Also changed it to look more like the original VodafoneUSBModem test by
adding another thread in the code.
Fixed macro definitions in u-blox test
gpio irq enable/disable

	- InterruptIn disable_irq/enable_irq
Added additional command line options for the build
reset to original settings
Added macro definition from command line

build_api.py now support macros defined at compile time, so build.py and
make.py can be used like this:

$ make.py/build.py <options> -DMACRO1 -DMACRO2=VALUE2 ...
Merge branch 'upstream_master' into dev_gpio_irq_endis
Merge pull request #88 from 0xc0170/dev_gpio_irq_endis

Dev gpio irq endis
Merge pull request #86 from pbrier/master

Issue #84 - Added command line source/build directory option
Added auto synchronization for the u-blox GSM modem test

Also changed the test to look more like the original VodafoneUSBModem SMS
test (added another thread).
Merge remote-tracking branch 'github/master'
fixed invalid include name
pyOCD development moved to https://github.com/OpenHDK/pyOCD
Added 'macros' keyword to build_api.py to allow building USB libraries.