Strip declarations when compiling a block.

I.e. not only for LAMBDA.  Currently enabled for LET and LET*.
Add and export PUSHNEW.
Add and export DO-(ALL/EXTERNAL)-SYMBOLS.
Fix return value.
Add package tests.
Rewrite FIND using SATISFIES-TEST-P
Rewrite POSITION using SATISFIES-TEST-P and add missing export
Rewrite REMOVE using SATISFIES-TEST-P
Tests for modified sequence functions
Add TEST-NOT keyword argument to TREE-EQUAL
Rewrite MEMBER using SATISFIES-TEST-P
Rewrite ASSOC using SATISFIES-TEST-P
Rewrite RASSOC using SATISFIES-TEST-P
Merge branch 'package-improvements' of https://github.com/Ferada/jscl into Ferada-package-improvements
Merge branch 'master' of github.com:davazp/jscl

# Please enter a commit message to explain why this merge is necessary,
# especially if it merges an updated upstream into a topic branch.
#
# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.
Merge branch 'satisfies' of https://github.com/orodley/jscl into satisfies-test

Conflicts:
	src/toplevel.lisp
Export _all_ standard symbols