Set the version number to 1.4.

Cherry-pick bug fixes for release candidate 2.

Include a fix for a regression reported on the mailing list.

https://lists.apache.org/thread/g206zssnxltdc88x2ovjg6zpdmtyb8qc

Remove `sis-webapp` module, since it is not ready.

Remove generation of C/C++ header files (not used anymore after remov…

…al of "sis-gdal" module).

More paranoiac check for rounding errors in `normalizeColumns()`.

Fix error in copyright year. It is too late for 1.0-RC1, but we commi…

…t this fix in case we want to do a RC2 or a 1.0.1.

https://lists.apache.org/thread.html/12a496ae3ba79ff96952d180c77bffa32de74e76a57223538782a98c@%3Cdev.sis.apache.org%3E

Tag Apache SIS 0.8, released on 2017-11-24.

Tag Apache SIS 0.7, released on 2016-05-27.

Tag Apache SIS 0.6, released on 2015-09-16.