Google Drive allows forward slashes (/) as filenames. GDriveFS fails with I/O error.

[agusdallalba]

Steps to reproduce:

1. Make a file/folder in the Google Drive web interface that includes a forward slash
2. Mount the Google Drive and run ls Result: ls: reading directory .: Input/output error.

Expected result: GDriveFS should treat these files and folders gracefully somehow. The official Google Drive client for windows replaces the slashes with undescores (Turns A/B into A_B). If the filename with underscores already exists it adds (1) to the name (So A/B and A_B turn into A_B (1) and A_B). Another option is, for example, to partially C-escape / into \x2f and \x2f into \\x2for partially URL-encode / into %2F and %2F into %252F.