Similar functions are provided in CL, but they operate on *arrays* when all they
really need are the *dimensions*. This sometimes proves an annoyance, and I
thought alexandria was a good place to implement these.

Salvador Fandino authored Apr 25, 2015 and Attila Lendvai committed Apr 27, 2015

Fixed problems:

1) Unintended variable capture affecting KEY, HASH-TABLE and DEFAULT
   FORMS
2) Multiple evaluation of the KEY and HASH-TABLE forms

- make it usable for other Lisps besides SBCL.
- TEST-OP runs tests both compiled and evaluated.

with-input-from-file
with-output-to-file
read-file-into-string
write-string-into-file
copy-stream
copy-file

	* alexandria.asd: Add dependency between `types.lisp' and
	`sequences.lisp', as the latter uses ARRAY-INDEX since recently.

Patch by Stelian Ionescu.

Added respective documentation in manual as well.

Added:
 * XOR
 * WHICHEVER
 * SWITCH, ESWITCH, CSWItCH
 * UNIONF, NUNIONF
 * ALIST-PLIST, PLIST-ALIST
 * ENSURE-CONS
 * NAMED-LAMDBA
 * DEFINE-CONSTANT
 * STRING-DESIGNATOR

Note:
 Documentation strings of many new operators are sorely lacking, particularly
 NAMED-LAMBDA and *SWITCH.