* add `@compileLog(...)` builtin function
- Helps debug code running at compile time
- See #240
* fix crash when there is an error on the start value of a slice
* add implicit cast from int and float types to int and float
literals if the value is known at compile time
* make array concatenation work with slices in addition to
arrays and c string literals
* fix compile error message for something not having field access
* fix crash when `@setDebugSafety()` was called from a
function being evaluated at compile-time
* fix compile-time evaluation of overflow math builtins.
* avoid debug safety panic handler in builtin.o and compiler_rt.o
since we use no debug safety in these modules anyway
* add compiler_rt functions for division on ARM
- Closes#254
* move default panic handler to std.debug so users can
call it manually
* std.io.printf supports a width in the format specifier
* add `setFnTest`, `setFnVisible`, `setFnStaticEval`,
`setFnNoInline` builtin functions to replace previous
directive functionality
* add `coldcc` and `nakedcc` as keywords which can be used as part
of a function prototype.
* `setDebugSafety` builtin can be used to set debug safety features
at a per block scope level.
* closes#169