Change echo for printf

rationale:
http://unix.stackexchange.com/questions/65803/why-is-printf-better-than-echo

fix #129
Add common linker script for MPIDE version 0023-*-20130817-test.
Include assembly vector table in chipKIT build.

* Added build step for assembly files in CORE
* Removed duplicate flags from AS build step
Update `HISTORY.md` about ChipKIT 2013 support
Auto detect and include libraries specified in `USER_LIB_PATH`

Fix #135
Use MAKEFILE_LIST to get the name of the make file

This way we don't assume the make file is 'Makefile' and it will
work even if it is named as 'makefile' or 'makefile-uno'

Fix #130
Adjust path to avrdude/avrdude.conf for MPIDE in Linux.
Merge pull request #137 from peplin/chipkit-avrdude-mac

Adjust path to avrdude/avrdude.conf for MPIDE in Linux.