Make fastboot command-line parsing a bit more like adb.

Only show all the help if asked to, and have a few more descriptive
syntax errors.

Also show the help on stdout rather than stderr.

Bug: N/A
Test: manually ran "fastboot flash"/"fastboot update"/"fastboot flashall"
Change-Id: I59abd60e58a56fe7e44da5116a702087c36e14ce
diff --git a/fastboot/fastboot.h b/fastboot/fastboot.h
index e30c6de..e3c60ae 100644
--- a/fastboot/fastboot.h
+++ b/fastboot/fastboot.h
@@ -66,7 +66,7 @@
 void fb_queue_command(const char *cmd, const char *msg);
 void fb_queue_download(const char *name, void *data, uint32_t size);
 void fb_queue_download_fd(const char *name, int fd, uint32_t sz);
-void fb_queue_upload(char *outfile);
+void fb_queue_upload(const char* outfile);
 void fb_queue_notice(const char *notice);
 void fb_queue_wait_for_disconnect(void);
 int64_t fb_execute_queue(Transport* transport);