Nearly all special errors are now handled gracefully, i.e. the
parser will be able to continue after encountering them. In some
cases the associated error range has been improved using the new
end attribute stack.
To achieve this the error handling code has been moved out of the
node constructors and into special methods in the parser.
A Nop statement will be inserted into statement lists if there are
any trailing comments in the list (which would otherwise not be
associated with any node).
The pretty printer output currently still contains a superfluous
newline.
Adding this as an option to avoid breaking people's tests.
Some of the test results show pretty clearly that we are incorrectly
assigning the same comment multiple times for nested nodes (mentioned
in #36).
When parsing on PHP 7 we will no longer be able to deal with
code that contains invalid octal literals. Currently we'll fatal,
after engine exceptions land we'll throw an exception instead.
Travis 5.2 seems to have changed the float output precision, so a test was
failing. Now the numbers in the expected output are also provided by PHP,
so they should be the same.
