MNT:add toggle function for PushButton and show different texts when …

[lvhuihui1988]

…pressed and released.

[lvhuihui1988]

EDM allows us to choose toggle function for pushbutton, we add the same function for pydm.

[codecov-commenter]

Codecov Report

Merging #773 (e4a44d0) into master (9ac9bd5) will decrease coverage by 0.03%. The diff coverage is 54.16%.

@@            Coverage Diff             @@
##           master     #773      +/-   ##
==========================================
- Coverage   58.92%   58.88%   -0.04%     
==========================================
  Files          91       91              
  Lines       10543    10571      +28     
==========================================
+ Hits         6212     6225      +13     
- Misses       4331     4346      +15     

Impacted Files	Coverage Δ
pydm/widgets/pushbutton.py	88.73% <54.16%> (-6.41%)	:arrow_down:
pydm/widgets/rules.py	70.94% <0.00%> (-1.12%)	:arrow_down:
pydm/widgets/base.py	90.76% <0.00%> (+0.45%)	:arrow_up:

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[YektaY]

Thank you for this PR, the PyDM team has decided to not include it in the main project, because the feature does not fit within our overall vision for PyDM. If you do have any other functionality you would like to push upstream, we would be happy to take a look. And we will be sure to respond in a more timely fashion going forward. Thank you again