ticket:10993: ICU4C version number to 54.1.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36357 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10972: improve --with-data-packaging docs


git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36363 251d0590-4201-4cf1-90de-194747b24ca1
ticket:11223: Remove unused data structure from RelativeDateTimeFormatterTest

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36365 251d0590-4201-4cf1-90de-194747b24ca1
ticket:11036 RBBI, check data header when opening.

git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36366 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10920: enable "io" library to build (with no APIs) with UCONFIG_NO_CONVERSION set.


git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36367 251d0590-4201-4cf1-90de-194747b24ca1
ticket:10989: fixup apidoc tags on deprecated layout engine. Also DO
build it by default still for this release. Add a note on
ParagraphLayout as well.


git-svn-id: http://source.icu-project.org/repos/icu/icu/trunk/source@36368 251d0590-4201-4cf1-90de-194747b24ca1