- replace PHP4 style class constructor function names (based on
  class name) with php 5 __construct()
Also remove some '&' reference operators used with objects
And add some object type hints

this group is skipped by default

it seems that different zlib versions behave different with corrupted files.
Some return false, some return whatever they still can read from the
file. the file now should no longer be readable by any version.

This also reverses the order of crypto protocols tried again. Using TLS
first again. related to #915

The code reading .bz2 compressed files did not correctly check for
possible read errors. In case of a corrupted file this could have led to
an infinite loop.

Thanks to Filippo Cavallarin from www.segment.technology for dicovering
this bug.

In an older version of PHP a file_exists() call would issue a warning
when the file did not exist. This was fixed in later PHP releases. Since
we require PHP 5.3 now, there's no need to supress any error here
anymore. This might even give a minor performance boost.

the filter() function can be chained between the accessor and the value
function to get a filtered value. When no filter allable is given in the
filter() function, stripctl() is used to strip all control chars (ASCII<32)

Examples:

  $INPUT->post->filter()->str('foobar');
  $INPUT->get->filter('myfilter')->int('baz');

this should test the correctness of the return value of is_ssl()
function based on various combinations of PHP environment variables

This avoids treating double slashes as single line comments in CSS when
they are used in a filter or content string.

closes #638

That commit did not test what it actually made for. Handling protocol
relative URLs in CSS.

This introduces an abstract base class that command line tools need to
inherit from. It provides a simple framework for registering accepted
command line options and provides commonly needed things like help
output and colored text.

Existing CLI scripts still need to be converted.

1. cachetime setting should only be applied to the cache_renderer
   class.  Previously it was applied to cache_parser (and by
   extension cache_handler).
2. two special cachetime values, -1 & 0, weren't handled, per
   FS#2183

To handle the cachetime setting, -1, disable caching, a new
property _nocache is added.  When that property is true, any cache
file must not be used and storecache() should not store any values

source maps are invalid for our dispatched sources and may even cause
problems. this makes sure any sourcemap declarations are stripped from
the output

This very basic test ensures that the useCache method works as
expected for simple scenarios. This test case fails without commit
a8795974 and then also triggers the
warning that was introduced in bc2ddb54