[MAKE.py] additional error handling when missing an option in private_settings.py

Adding an error handling.

make.py with the option -n PROGRAM_NAME wants to have a test_alias
variable in private_settings.py. Without this alias and with a wrong
PROGRAM_NAME an error message is generated because of a missing else
branch.
Merge pull request #568 from ohagendorf/make_py

Tools: make.py - additional error handling when missing an option in private_setttings.py
[NUCLEO_F091RC] Minor change in pin definition

There is no PWM on PB_3 for this device.
Merge pull request #571 from bcostm/master

HAL: NUCLEO_F091RC - Minor change in pin definition
Add v7.1.0 of the Nordic softdevice.
This is necessary in order to utilize the additional 16KB of SRAM in the updated nRF51822.
mostly white space diffs; and line endings
Merge pull request #575 from toyowata/master

HAL : LPC824 - Fix SPI1 SWM table
Merge pull request #574 from rgrover/master

updating to v7.1.0 of the Nordic soft-device.
In tests NET_1 and NET_7 changed URL to files from mbed.org to developer.mbed.org. Reason: online IDE was moved to developer subdomain and NET1 and NET-7 tests were failing