fix(*): import rxjs in a proper way. Closes #172

[rychkog]

No description provided.

[codecov]

Codecov Report

Merging #173 into develop will increase coverage by 0.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop     #173      +/-   ##
===========================================
+ Coverage    95.84%   95.86%   +0.01%     
===========================================
  Files           22       23       +1     
  Lines          819      822       +3     
  Branches       120      120              
===========================================
+ Hits           785      788       +3     
  Misses          16       16              
  Partials        18       18

Impacted Files	Coverage Δ
src/tree.ts	93.11% <100%> (ø)	⬆️
src/rxjs-imports.ts	100% <100%> (ø)
src/draggable/node-draggable.service.ts	100% <100%> (ø)	⬆️
test/test.ts	100% <100%> (ø)	⬆️
src/tree.service.ts	100% <100%> (ø)	⬆️
src/menu/node-menu.service.ts	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d776886...90459d5. Read the comment docs.