Fix name of FREEDOM-KL25Z demo Eclipse project.
Set KL25Z demo Eclipse ChibiOS root path.

It is set in Eclipse Project Properties | Resource | Linked Resources |
Path Variables tab, named CHIBIOS and points to ../.. relative to the
project itself.
Add pin name comments in pal_default_config.

Added inline comments for all pin names in the pal_default_config
definition so it is easier to find the right element among all 32
elements in the array initializer.
Fix FRDM-KL25Z SWD_CLK/SWD_DIO/RESET pin defaults.

By default they were set as GPIO inputs, so the debug adapter could not
communicate with the KL25 MCU once the program started and changed the
SWD and RESET_b pins to GPIO configuration.

FRDM-KL25Z Reset/SWD pin assignments:

===== =========
Pin   Function
===== =========
PTA0  SWD_CLK
PTA3  SWD_DIO
PTA20 RESET#
===== =========
Improve default pin settings for FRDM-KL25Z.

Pins that don't exist on the MCU are set to UNCONNECTED.
Pins that are not dedicated to a particular use are set to INPUT_ANALOG
(we don't want them to be Hi-Z inputs if they are unconnected).
Pins that have special purposes such as RESET_b and SWD pins are set to
their special functions.
Fix UARTx_S1 flag clearing in serial_lld.c.

The flags in S1 are write-1-to-clear, so the |= operation was actually
clearing *all* set flags in the S1 register regardless.
Fix blue LED (PTD1) assignment: set as output.
Merge pull request #1 from cdbennett/FREEDOM-KL25Z_Board_pin_init

Improve FREEDOM-KL25Z board pin initialization
Merge pull request #3 from cdbennett/KL2x_serial_flag_clearing

Fix UARTx_S1 flag clearing in serial_lld.c.
Merge pull request #2 from cdbennett/FREEDOM-KL25Z_Demo_Eclipse_project

Fix Eclipse project file for FREEDOM-KL25Z Eclipse demo