Avoid carrying over test status when no node version is installed

When sourcing nvm.sh, if there are no version of node installed the command
`nvm ls default` silentry fails, however it's return status code (`$?`) is
still set to non-zero, which means an error.

This patch simply avoids this issue by making sure the status code after
sourcing is ok so that people that put the returned status codes in their
command line prompt don't get an error every time `nvm.sh` is sourced.
remove continue from curl arg. nodejs.org doesnt seems to support continue, CDN effect perhaps?
make ls-remote work with no parameters in linux
Merge pull request #150 from tlevine/master

I added tests.
Support binary installs

Heavily inspired by isaacs/nave
Merge pull request #152 from Marsup/binary-installs

Support binary installs
Merge pull request #148 from nathan-lafreniere/master

Fixes ls-remote with no parameters in linux
Merge pull request #106 from ghost/master

nodejs.org doesnt seem to support resuming partial downloads
Merge pull request #96 from caio/dont-fail-on-source

Avoid carrying over test status when no node version is installed
Update README.markdown
Add ls-remote to autocomplete
updated list of commands
Merge remote-tracking branch 'upstream/master'

Conflicts:
	bash_completion
Merge pull request #154 from mikedeboer/master

one more: list-remote
Making ARM stop downloading x86 binaries
Merge pull request #155 from jwietelmann/master

NVM downloading x86 binaries instead of source for ARM Linux box
Account for uname -a i686
Merge pull request #160 from wlaurance/master

i686 architecture
Checksum support for binary downloads

Checksum support for source downloads

Closes #159
Merge pull request #161 from wlaurance/master

Checksum checking