Properly doing a minor revision.
[chore] remove extern "C" from eh_personality since it's no longer needed.

[bug fix] BREAKING! Fix a bug with the main routine which was no longer able to build with updated versions of rust. This change removes the extern "C" directive from the panic handler.
[bug fix] No longer reserving pins 7 and 8 for kernel purposes
[feature] Add begin_with_external_power to i2c which will assume an externally-biased pull-up. Useful if you are working with less-than 3v3 components.
[chore] Add a new F_CPU variable and CLOCK_CPU to help with precise timing
[chore] Give some pin enums the ability to be cloned

This release includes the following features and bug fixes:

[bug fix] Fixed a critical bug with pad muxing. (it never worked before, now it does).
[chore] update formatting in `pins.rs`

This release includes the following features and bug fixes:

• [feature] A prelude file
• [feature] Add a ref_count() method to help debug memory issues
• [feature] A new using!({ }) directive which automatically releases all memory created within the macro
• [chore] Updates to the README, better reflecting startup steps
• [chore] Updated USB PID/VID to use the official teensycore reservation
• [chore] Refactored the debug tools to have better memory management by invoking the using!({ }) macro

This release includes a breaking change to the linker.ld file. The linker file is cached at build time, so to clear the cache, please delete any out directories that were generated as part of the build process (in your local projects). This will force a new linker file download, and allow the usb features to work.

This release includes the following features and bug fixes:

• [feature] USB OTG Driver
• [feature] USB Serial
• [feature] Analog Pin Support (analogRead())
• [bug fix] Fixed a bug with i2c which prevented proper termination signals from emitting
• [bug fix] Change how memory is reclaimed to improve performance
• [bug fix] Fix critical bug in the buffer data structure which caused buffer overflow in some situations

This release includes a breaking change. serio::serial_write_str now requires a mutable reference to an Str object and will automatically call drop on it.

This release includes the following features and bug fixes:

• [Feature] i2c support with a similar interface to Arduino
• [Bug fix] Updated build-template.sh which includes proper optimization settings
• [Bug fix] Serial subscribes to fewer interrupt events, which prevents dropped packets
• [Bug fix] Serial_write_str now automatically drops the string after use, which fixes a memory leak
• [Bug fix] System clock is improved
• [Bug fix] irq was cleared before servicing which caused some unintended behavior

Updates to wait method so it is closer to actual time.