Remove some unused or unneeded proguard rules

[Jawnnypoo]

Turns out we don't need a few of these as they were for when we were using a deprecated Notification class from API 23, and the SSLCertificateSocketFactory on other implementations of the Http Client.

In addition, I am removing the lines that keep source files and line numbers, as this should be decided on/configured by the end consumer, as they might not actually want those things to be kept in their end APK.

[codecov]

Codecov Report

Merging #649 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #649      +/-   ##
============================================
- Coverage     52.88%   52.86%   -0.02%     
  Complexity     1676     1676              
============================================
  Files           131      131              
  Lines         10146    10146              
  Branches       1408     1408              
============================================
- Hits           5366     5364       -2     
- Misses         4338     4339       +1     
- Partials        442      443       +1

Impacted Files	Coverage Δ	Complexity Δ
...se/src/main/java/com/parse/ParseKeyValueCache.java	45% <0%> (-2%)	16% <0%> (ø)

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[rogerhu]

rebase