Limit length of input lines and substitution expansion.
Mitigate the danger of DoS attacs using
specially crafted rST input (cf. bug #381).
The default value of 10 000 characters should suffice for
legitimate use cases (e.g. long paragraphs in auto-wrapping editors
or extensive creative use of substitutions).
Applications processing untrusted rST might wish to lower this
limitation (together with other safety measures described in
docs/howto/security.txt).
Unsupervised processing of untrusted rST input should always
be safeguarded with limits on processing time and memory use.
git-svn-id: http://svn.code.sf.net/p/docutils/code/trunk@8565 929543f6-e4f2-0310-98a6-ba3bd3dd1d04