Changes to FastaReferenceWriter

[lbergelson]

• make sure the OutputStreams are always buffered
• change close behavior to be more likely to close all output streams in the event of an early shutdown
• loosen restriction from BufferedWriter to Writer in SAMSequenceDictionaryCodec and SAMTextHeaderCodec

[codecov-io]

Codecov Report

Merging #1285 into master will increase coverage by 0.006%. The diff coverage is n/a.

@@              Coverage Diff               @@
##             master     #1285       +/-   ##
==============================================
+ Coverage     67.49%   67.496%   +0.006%     
  Complexity     8150      8150               
==============================================
  Files           558       558               
  Lines         33365     33365               
  Branches       5608      5608               
==============================================
+ Hits          22518     22520        +2     
+ Misses         8658      8657        -1     
+ Partials       2189      2188        -1

Impacted Files	Coverage Δ	Complexity Δ
src/main/java/htsjdk/samtools/util/HttpUtils.java	32.258% <0%> (-3.226%)	2% <0%> (-1%)
...samtools/util/AsyncBlockCompressedInputStream.java	76% <0%> (+4%)	13% <0%> (+1%)	:arrow_up: