move proof sessions for the standard library files to examples/stdlib

.gitignore

examples/regtests.sh

...es/stdlib/array/array_ArrayPermut_exchange_permut_sub_1.v

...s/stdlib/array/array_ArrayPermut_permut_sub_weakening_2.v

examples/stdlib/array/why3session.xml

examples/stdlib/array/why3shapes.gz

examples/stdlib/bintree/why3session.xml

examples/stdlib/bintree/why3shapes.gz

theories/bintree/why3session.xml