synthesize.h now contains the definitions STRESS_IS_... that should be used with code related to syllable stress.

Note that isBreak and other defines were renumbered so that stress definitions could have values 0-6.

Possible TODOs:
1. Unify with terms used with phonemes, i.e. keywords like isDiminished in compiledata.c and stress_type in phsource/phonemes
2. Add functionality and documentation about STRESS_IS_PRIORITY and STRESS_IS_EMPHASIZED

See issue #8, https://github.com/espeak-ng/espeak-ng/issues/8

There might still be some ints that could be changed to boolean.

Possible regressions in fifo.c:
int fifo_is_busy() and int fifo_is_command_enabled() used to return an int. Now they return a boolean. This might cause problems on systems where stdbool true/false is something else than 1/0.

This reverts commits 0cc0300328 to
38d15f8f90.

The 0cc03003 commit breaks MBROLA voice support. As such, there
may be other breakages in those commits.

The libespeak files are supposed to be C code, so use C linkage
for all the functions defined in that code when they are being
referenced in the C++ code (i.e. espeakedit).

Fix bug, use of the command-line  "espeakedit --compile" produced phoneme data
in which vowels started at full amplitude instead of gradual increase.

Fix bug:  SSML <break time=""> with values greater than 23 seconds were ignored
due to arithmetic overflow.

Phoneme definition files:
Added new function:  ChangeNextPhoneme().

Language changes include: da, en, fa, gu, hu, it, nl, pt, ta

Started new language: eu (Basque).

*_rules files:
Allow $p_alt1, $p_alt2, etc in pre-conditions.  The rule matches if the
characters before the current point in the word occur as an entry in the
*_list file with the corresponding $alt attibute.

Added condition $list.  This is similar to $p_alt etc, but examines
all words in the *_list file which don't have the $only attribute.


git-svn-id: https://espeak.svn.sourceforge.net/svnroot/espeak/trunk@374 d46cf337-b52f-0410-862d-fd96e6ae7743

Language changes: bn, en, da, it, pt.
Started new language, gd (Scottish Gaelic).
 

git-svn-id: https://espeak.svn.sourceforge.net/svnroot/espeak/trunk@371 d46cf337-b52f-0410-862d-fd96e6ae7743