Fix: various errors during installation

[digglife]

1. Add Missing space before the git url. This problem causes git clone failure, so the whole share object building process doesn't work.

2. Remove sudo statements. If the package path is not writable to current user, then it should not be. We should let user to decide whether to use sudo instead of prompt password in the middle of installing (Actually install to system site-packages with admin privilege is a bad practice). Also, if user is using virtualenv or install with --user, it's perfectly fine without sudo.

3. Avoid echoing the output because system output is unpredictable. It could be multiple lines, so os.system("echo ", output.decode("utf-8")) could end up executing the following shell command

   echo the first line
   the second line
   the third line
   

   the second line and the third line will be executed as normal shell command.

   We don't need to use echo to print out the result.

4. os.exit(1) should be sys.exit(1)