Make autoloader more PSR-4 (#268)

Drop superfluous newlines before help text

support -h and --help standard options

Tweaked a phpdoc description

Run test_old using php -n

Xdebug is killing performance.

Add setReturnType() method to function/method builders

Also support scalar type hints in existing setTypeHint() method on params.

Fix .travis.yml

Run test_old against php-src on travis

"Fix" HHVM build

Add string kinds and doc string labels

Scalar\String_ and Scalar\Encapsed now have an additional "kind"
attribute, which may be one of:

* String_::KIND_SINGLE_QUOTED
* Str

Add string kinds and doc string labels

Scalar\String_ and Scalar\Encapsed now have an additional "kind"
attribute, which may be one of:

* String_::KIND_SINGLE_QUOTED
* String_::KIND_DOUBLE_QUOTED
* String_::KIND_NOWDOC
* String_::KIND_HEREDOC

Additionally, if the string kind is one of the latter two, an
attribute "docLabel" is provided, which contains the doc string
label (STR in <<<STR) that was originally used.

The pretty printer will try to take the original kind of the string,
as well as the used doc string label into account.

show more ...

Add two files to test_old skip list

The parse after pretty printing differs here, because these tests
contain nop (;) statements, which the pretty printer does not
preserve.

Fix comment reformatting for some cases

It did not correctly deal with non-standard comments containing
indented lines.

Add --verbose option to test_old/run.php

Fix nop statement comment assignment

Keep around the start attributes on the lookahead token around in
a separate parser property.

Make canonicalization less aggressive

Another fix for B"" handling

The lexer fix also need to account for uppercase B.

Handle uppercase B"" prefix

Deduplicate attribute assignment code a bit

Deprecate setters on Comment

No point in making it mutable

Add start file offset to Comments

Fix Serializer/XML test output indent

This causes a failure here, but not on another machine, not sure
why.

Add sanity check for leaveNode() return value

Better Travis configuration

* Enable Travis cache for Composer
* Use `--prefer-dist` over `--prefer-source` to download less and
make it faster

Remove internal LNumber::parse() method

Combine it into ::fromString(), as they both do the same checks.

Move "kind" attribute handling out of lexer

Doesn't belong there and will cause issue with multiple assignments.