[BEAM-1455] Flag-Coding remains when subsetting
replace manual header parsing with a generic parsing class
removed TODOs that are no loner applicable
remove additional line breaks
keep header entries in original order
[BEAM-1622] ENVI reader shall have metadata
include empty values, but exclude them from array results
[BEAM-1621] ENVI reader shall consider "data ignore value"
[BEAM-1614] ENVI Reader shall consider 'Full width at half maximum'
[BEAM-1623] ENVI reader shall read data in BIP format
[BEAM-XXXX] ENVI reader shall support classification
simplify
copy metadata nodes of components products into main product