This adds a version of `almostEqual` (which was already available for
floats) thata works with `Complex[SomeFloat]`.
Proof that this is needed is that the first thing that the complex.nim
runnable examples block did before this commit was define (an
incomplete) `almostEqual` function that worked with complex values.
(cherry picked from commit d8e1504ed1)
* CIs: attempt to use csources_v1
* also updated the BSDs
* also updated azure pipelines
* std modules should not itself use the 'std/' import dir...
* compiler has to be careful with std/ for v1 booting
* Improve documentation for complex
Add missing doc comments
* Add runnableExample
Add links for principal values
Optimize `-`
Change var to let
* Use std prefix for imports
* remove `**`
* const `im` can now be used with Complex64
* converters from float|int to Complex are replaced by procs
* converters between various Complex types must stay to allow usage
of `im` with Complex64
* limit types for `+`, `-`, `/`, and `*` between Complex and float
* add `pow` for Complex and a number
* complex type changes
* unpublish approximation function
