The more proper place for shell scripts dedicated for development, and
releasing PHP should be the scripts/dev directory. Having a cleaner root
project directory helps find the main README.md and files relevant to
install PHP.

These scripts are also used by the release managers mostly who create
release packages and aren't used often by the majority of developers
working on and installing PHP.

This patch removes generated lexer files by re2c during the build
process so they are not tracked by Git yet can be still shipped when
PHP is released. The genfiles script additionally provides generation
of these lexer files when creating a release of the PHP source code.

The genfiles script refactorings:
- added file header
- echoing steps instead of comments
- cleaning only lines starting with `#line`
- eval removed in favor of direct executed commands
- the debug mode `set -x` removed
- script can be called from any path
- improved comments

The parser files for ext/json are generated by bison from the *.y file.
Parser files in Zend and sapi/phpdbg already follow such approach of
these files being ignored from tracking in the Git repository and they
are shipped via the release packages later on. This way the end users
still don't need to have bison dependency installed to install PHP.

The genfiles script was refactored to generate the ext/json parser and
lexer files.

The parser files for phpdbg are generated by bison from the *.y file.
Parser files in Zend already follows such approach of these files being
ignored from tracking in the Git repository and they are shipped via
the release packages. This way the end user still don't need to have
bison dependency installed to install PHP.

The genfiles script was refactored to generate the phpdbg parser and lexer
files.

Empty comment in phpdbg parser y template file has been changed to the
YACC compliant /* empty */ instead of custom one.

The two are more logically connected together in the Zend directory.

This patch adds missing newlines, trims multiple redundant final
newlines into a single one, and trims redundant leading newlines.

According to POSIX, a line is a sequence of zero or more non-' <newline>'
characters plus a terminating '<newline>' character. [1] Files should
normally have at least one final newline character.

C89 [2] and later standards [3] mention a final newline:
"A source file that is not empty shall end in a new-line character,
which shall not be immediately preceded by a backslash character."

Although it is not mandatory for all files to have a final newline
fixed, a more consistent and homogeneous approach brings less of commit
differences issues and a better development experience in certain text
editors and IDEs.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_206
[2] https://port70.net/~nsz/c/c89/c89-draft.html#2.1.1.2
[3] https://port70.net/~nsz/c/c99/n1256.html#5.1.1.2