docs: Merge xsd-fu prerequisites into build instructions

Merge source code page with build instructions
Move build instructions to the top since it's got a wider
scope than contributing--non-developers need this
docs: Correct incomplete sentence
docs: Correct genshi notes
docs: Simplify crossreference
docs: Rework git links
docs: Further rework git links
merge develop -D org: PR 983 (Woolz: make sure the service is initialized when calling openBytes (rebased onto develop))
merge develop -D org: PR 1154 (Leica: prevent exception when linking EmissionFilter)
merge develop -D org: PR 1191 (FakeReader improvements, part 1)
merge develop -D org: PR 1199 (Nikon .nd2 fixes, part 3 (rebased onto develop))
merge develop -D org: PR 1200 (Fix off-by-one in LZW decoding)
merge develop -D org: PR 1205 (TIFF: correctly account for ```fakeBigTiff``` when reading IFD entries)
merge develop -D org: PR 1208 (docs: Merge xsd-fu prerequisites into build instructions (develop))
merge develop -D org

Repository: openmicroscopy/bioformats
Excluded PRs:
  # PR 1054 qidane 'Additional annotation points throughout the model' (exclude comment)
  # PR 1177 rleigh-dundee 'specification: Add metadata for HDF5 embedding' (exclude comment)
  # PR 978 berl 'Add writing of .v3draw format for easy loading with Vaa3D.' (user: berl)
  # PR 857 melissalinkert 'Initial support for Zeiss .lms files' (label: exclude)
  # PR 816 melissalinkert 'Add support for multi-channel Volocity Clipping datasets' (label: exclude)
  # PR 858 melissalinkert 'Initial support for Veeco AFM data' (label: exclude)
  # PR 1136 melissalinkert 'Add initial support for reading BinaryOnly OME-TIFF datasets (rebased onto develop)' (label: exclude)
  # PR 1204 rleigh-dundee 'cpp: Add PixelBuffer<> and VariantPixelBuffer' (exclude comment)
  # PR 1161 sommerc 'Initial CellH5 Reader class' (user: sommerc)
  # PR 1141 LeeKamentsky 'Reader for Amaris FlowSight .cif format' (label: exclude)
  # PR 1015 qidane 'Messy binary' (exclude comment)
Already up-to-date.

Merged PRs:
  # PR 983 melissalinkert 'Woolz: make sure the service is initialized when calling openBytes (rebased onto develop)'
  # PR 1154 melissalinkert 'Leica: prevent exception when linking EmissionFilter'
  # PR 1191 melissalinkert 'FakeReader improvements, part 1'
  # PR 1199 melissalinkert 'Nikon .nd2 fixes, part 3 (rebased onto develop)'
  # PR 1200 melissalinkert 'Fix off-by-one in LZW decoding'
  # PR 1205 melissalinkert 'TIFF: correctly account for ```fakeBigTiff``` when reading IFD entries'
  # PR 1208 rleigh-dundee 'docs: Merge xsd-fu prerequisites into build instructions (develop)'
Generated by OMERO-5.1-merge-push#325 (http://ci.openmicroscopy.org/job/OMERO-5.1-merge-push/325/)