Disabled the HAVEGE random generator by default

Rationale: The HAVEGE random generator has too many caveats to be a
standard generator that people rely on. The HAVEGE random generator is not
suitable for virtualized environments. In addition the HAVEGE random
generator is dependent on timing and specific processor traits that
cannot be guaranteed by default on compile time.

Our advice: only use HAVEGE as an additional random source for your
entropy pool, never as your primary source.
(cherry picked from commit 08f06cf49f3e71258bc1a9350de1c297f22e4ec9)

Conflicts:
	ChangeLog
pem_read_buffer() already update use_len after header and footer are read

After header and footer are read, pem_read_buffer() is able to determine
the length of input data used. This allows calling functions to skip
this PEM bit if an error occurs during its parsing.
(cherry picked from commit 9255e8300e550b548b54603c77585921f442e391)
x509parse_crt() now better handles PEM error situations

Because of new pem_read_buffer() handling of when it writes use_len,
x509parse_crt() is able to better handle situations where a PEM blob
results in an error but the other blobs can still be parsed.
(cherry picked from commit 6417186365f4a73a719fff754fefe8edcef2bc28)

Conflicts:
	ChangeLog
ssl_parse_certificate() now calls x509parse_crt_der() directly
(cherry picked from commit 1922a4e6aade7b1d685af19d4d9339ddb5c02859)

Conflicts:
	library/ssl_tls.c
Changed x509parse_crt_der() to support adding to chain.

Removed chain functionality from x509parse_crt() as x509parse_crt_der()
now handles that much cleaner.
(cherry picked from commit d6d4109adc01417abde44b3325d8438b584de5e5)
Added missing free()
(cherry picked from commit ff3a4b010b24c0293c3cefc1c8582b23775e1870)
Fixed values for 2-key Triple DES in cipher layer
(cherry picked from commit 2be71faae4df9f97a700e7e813dad7b544492339)

Conflicts:
	ChangeLog
Prepared for PolarSSL release 1.1.7
Added Security note (Advisory 2013-03) in ChangeLog
(cherry picked from commit 016ea076e72d771137d283958714e17368e3c049)

Conflicts:
	ChangeLog
ssl_write_certificate_request() can handle empty ca_chain
(cherry picked from commit 21360ca4d45c47f16952fa1f75c21600c4e26d7e)

Conflicts:
	library/ssl_srv.c