Patch for bug #67839 (mysqli does not handle 4-byte floats correctly)

Before the patch, a value of 9.99 in a FLOAT column came out of mysqli
as 9.9998998641968. This is because it would naively cast a 4-byte float
into PHP's internal 8-byte double.
To fix this, with GCC we use the built-in decimal support to "up-convert"
the 4-byte float to a 8-byte double.
When that is not available, we fall back to converting the float
to a string and then converting the string to a double. This mimics
what MySQL does.
Fix failing tests
Unused variable
Fixed initializing
Update Version Number :)
Bump version to 7.0.0-dev
Merge branch 'master' of git.php.net:php-src

* 'master' of git.php.net:php-src:
  Update Version Number :)
  Fixed initializing
  Unused variable

Conflicts:
	main/php_version.h
Behavoir of func_get_arg() and func_get_args() was changed in PHP7.
Now they show current values of variables corresponded to passed arguments instead of originally passed values.
Parameters with duplicate names are not allowed anymore in PHP7.
Fixed build after version number bumped
Remove old version PHP supports
Add copyright header
Merge branch 'master' of https://git.php.net/repository/php-src

Conflicts:
	ext/mysqli/mysqli_api.c
Fixed PHP6 unicode related tests
Fixed PHP6 unicode related tests
Fixed version check
Fixed version checking
Better version checking
Better version checking
Better version checking