Add --report-planning-failure option to cabal-install
Fix warnings
Save solver log on planning failure
Generate build summaries for all targets (closes #1189)

Now packages specified by directory or URL work with the --build-summary
option.
Describe "cpp-option" field
Reduce verbosity on a solver build reporting failure
Simplify back to just one variant of BuildReport.new
s/2.15/2.14.4/

See https://github.com/haskell/cabal/issues/1721#issuecomment-52210898
reword help text in allow-newer
packages -> dependencies