add tilde, following Symbolics; fix issue from #425

[jverzani]

• add ~ as an alternative to lhs \Equal[tabl] rhs or Eq(lhs, rhs) so that comparisons with Symbolics are easier.
• fix space issue exposed in response to issue adjoint(a) != conj(a) for a::Sym #425

[codecov-commenter]

Codecov Report

Merging #426 (93404b7) into master (5a98def) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #426      +/-   ##
==========================================
- Coverage   54.02%   54.02%   -0.01%     
==========================================
  Files          18       18              
  Lines        1155     1168      +13     
==========================================
+ Hits          624      631       +7     
- Misses        531      537       +6     

Impacted Files	Coverage Δ
src/constructors.jl	88.46% <ø> (ø)
src/mathfuns.jl	68.18% <33.33%> (-1.23%)	⬇️
src/numbers.jl	52.48% <60.00%> (+2.83%)	⬆️
src/types.jl	35.41% <0.00%> (-5.06%)	⬇️
src/matrix.jl	71.62% <0.00%> (-0.85%)	⬇️
src/lambdify.jl	93.22% <0.00%> (-0.12%)	⬇️

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