support hooks correctly

Full Changelog: 2.2...2.3

stm32 core support

What's Changed

• Build vars by @jscrane in #30
• Menu items by @jscrane in #31
• add more variables from platform spec + bugfixes by @jscrane in #33
• processing menu-items automatically by @jscrane in #35
• Stm32 menus by @jscrane in #36
• Common upload target by @jscrane in #38
• update docs + attiny bugfix by @jscrane in #40

Full Changelog: 2.1...2.2

2.1

Tracking cores' updates: many small changes and improvements.

2.0

Complete rewrite using GNU make magic to parse boards.txt and platform.txt. This makes it much more tolerant of platform updates.

v1.0 (final)

This is as far as I wanted to take this version of uC-Makefile