Add internal profiling with `TimerOutputs`

[codecov[bot]]

Codecov Report

Merging #54 (b50fa6e) into master (713b1e4) will decrease coverage by 0.41%. The diff coverage is 86.41%.

:exclamation: Current head b50fa6e differs from pull request most recent head 69b33b8. Consider uploading reports for the commit 69b33b8 to get more accurate results

@@            Coverage Diff             @@
##           master      #54      +/-   ##
==========================================
- Coverage   90.08%   89.67%   -0.41%     
==========================================
  Files          22       23       +1     
  Lines        1664     1695      +31     
==========================================
+ Hits         1499     1520      +21     
- Misses        165      175      +10     

Impacted Files	Coverage Δ
src/timings.jl	0.00% <0.00%> (ø)
src/newton_propagator.jl	97.56% <95.23%> (+0.50%)	:arrow_up:
src/arnoldi.jl	100.00% <100.00%> (ø)
src/cheby.jl	95.23% <100.00%> (+0.23%)	:arrow_up:
src/cheby_propagator.jl	95.65% <100.00%> (+0.09%)	:arrow_up:
src/controls.jl	94.40% <100.00%> (ø)
src/newton.jl	93.61% <100.00%> (+0.28%)	:arrow_up: