Fixed up some small bugs (e.g., pid -> proc)

doc/cheat.txt

@@ -32,7 +32,7 @@ Subforms are implicitly backquoted.
 
 Using process forms in Scheme:
     (exec-epf . EPF)	; Nuke the current process.
-    (& . EPF)		; Fork process in background. Return pid.
+    (& . EPF)		; Fork process in background. Return proc object.
     (run . EPF)		; Run process. Return exit code.
 
     (& . EPF) = (fork (lambda () (exec-epf . EPF)))
@@ -67,8 +67,8 @@ run/file*, that take thunk arguments for the subprocess.
     a port read returns EOF, the current set of seed values are
     returned as multiple values.
 
-(run/port+pid  . EPF) -> [port fixnum]
-(run/port+pid* THUNK) -> [port fixnum]
+(run/port+proc  . EPF) -> [port proc]
+(run/port+proc* THUNK) -> [port proc]
 
 (run/collecting  FDS . EPF) -> [port ...]
 (run/collecting* FDS THUNK) -> [port ...]
@@ -274,16 +274,16 @@ Derived procedures:
 
 (suspend)
 
-(fork [thunk]) -> pid or #d
-(%fork [thunk]) -> pid or #f
+(fork [thunk]) -> proc or #d
+(%fork [thunk]) -> proc or #f
 
-(fork/pipe  [thunk]) -> pid or #f
-(%fork/pipe [thunk]) -> pid or #f
+(fork/pipe  [thunk]) -> proc or #f
+(%fork/pipe [thunk]) -> proc or #f
 
-(fork/pipe+  conns [thunk]) pid or #f
-(%fork/pipe+ conns [thunk]) pid or #f
+(fork/pipe+  conns [thunk]) proc or #f
+(%fork/pipe+ conns [thunk]) proc or #f
 
-(wait [pid]) ->  status [pid]
+(wait [proc/pid]) ->  status [proc]
 
 (call-terminally thunk)
 
@@ -301,8 +301,8 @@ Derived procedures:
 
 (pid) -> fixnum
 (parent-pid) -> fixnum
-(process-group [pid]) -> fixnum
-(set-process-group [pid] pgrp)
+(process-group) -> fixnum
+(set-process-group [proc/pid] pgrp)
 
 (user-login-name) -> string
 (user-uid) -> fixnum 
@@ -359,7 +359,7 @@ command-line-arguments
 
 ** Signal system
 
-(signal-process pid sig)
+(signal-process proc/pid sig)
 (signal-procgroup prgrp sig)
 (pause-until-interrupt)
 (sleep secs)