lang: Make app build optional

lang: Split in to library and executable

scripts: Rewrite check to look in subdirectories

lang: Run clang-format

lang: Add error handling functions

lang: Move symbols to own file

lang: Fix copyright header

lang: Symbols are ints not indices

lang: Add argstack

lang: Add vtable

lang: Make operations thread safe

lang: Add object test code

Merge pull request #17 from LuminaSensum/RFC_clock ...

Add a high-resolution real-time clock

Clock: Add ability to convert from microseconds to kernel time ...

This functionality allows us to ask the kernel to schedule events
based on a high resolution real-time clock.

An example in main waits until the next second.

Clock: Combine clocks to create a high resolution real-time clock ...

The kernel clock is high resolution but only tracks uptime.
The RTC clock is low resolution but tracks real time.
The NTP clock is high resolution but costly to access.

We can combine the kernel clock with a real-time clock of any type
by sporadically calculating the time the system was booted at then
adding the kernel's uptime to it whenever we need a new clock.

Clock: Clean up and document the code

Clock: Use microseconds instead of struct timeval ...

timevals are a little annoying to work with compared to just microseconds,
so switch to using them for our clock API.

Clock: Print microseconds in ISO 8601 strings

Clock: Add _now suffix and variants for clock functions ...

Currently the clock code implicitly grabs the current time.
Add variants that let you pass in your own time value, and specify
extra _now functions that use the current time.

CMakeLists: Apply compile options to Mbed too ...

This was my original intention but I guess I had things in the wrong order.

main: Disable color tracing ...

Color tracing was really messing with grabserial and minicom.

Merge pull request #16 from LuminaSensum/networking_rework ...

NetworkHandler: make status callback private, reorder functions

NetworkHandler: make status callback private, reorder functions ...

The status callback function now gets privately declared at the earliest
possible moment, to both allow for reordering of code and avoid calling
this function directly from any other part of the code

* void changed to static void in status_callback declaration
* this now makes it possible to define network_init before
status_callback, as status_callback is declared much earlier

Merge pull request #15 from LuminaSensum/sntp ...

Add SNTP clock syncing

sntp: clang-format

sntp: Timeout if gethostbyname fails

main: Setup and sync clock when 3 presses are read

Clock: Add our clock ...

This clock is intended to be used to get a timeval with sub-second
accuracy and convert it back and forth between kernel and real time.

NetworkHandler: All access to the underlying NetworkInterface ...

We need this to actually use the network.

sntp: Add SNTP fork ...

This fork of SNTP uses code from https://github.com/howerj/sntp with
many changes by Casey and I to run on mbed.