db_demo sim db.py updates

 1) Incorporate threads and demonstrate concurrent tasks:
    a) multiple modifications of a tool parameter
    b) multiple adds/removals of  tool numbers
 2) Implement synchronization of LinuxCNC tooldata with
    the sim database for toolno additions/removals and
    parameter changes
 3) handle disallowed toolno additions if:
       interp not idle
 4) handle disallowed toolno removals if:
       interp not idle
       toolno in spindle
 5) handle disallowed toolno modifications if:
       toolno in spindle
 6) Incorporate history logging to db file
 7) handle SIGINT (ctrl-c) for standalone testing
 8) handle SIGUSR[12] for starting tasks outside of application
 9) Add detection/message for:
      unsupported letters in params
      unknown toolnos in commands
10) adapt base.inc to allow all coordinates
1l) misc code cleanups and notes

Notes:
1) no api changes
2) When a db application adds or removes tool numbers
   (after initialization), a call to tooldb_tools() must be
   submitted with an updated user_tools list.   The application
   can then synchronize LinuxCNC using the load_tool_command.

Author: dngarrett

configs/sim/axis/db_demo/README

@@ -2,17 +2,20 @@ db_ran.ini       random_toolchanger
 db_nonran.ini nonrandom_toolchanger
 
 Each config starts with:
-  tool    numbers 10--19
-  pockets numbers 11--20
+  tool numbers 10--19
 
-tool 10 in pocket 11
-tool 11 in pocket 12
-...
+A number of tools are set with identical
+tool diameters to demonstrate tool selection
+based on accrued tool time.
+
+The config runs separate tasks to
+  a) modify a tool parameter
+  b) add/remove tool numbers
 
 Usage (for db_nonran.ini):
 
 1) In a terminal, start as
-$ linuxcnc db_nonran.ini
+$ linuxcnc ./db_nonran.ini
 F1 --------- Estop off
 F2 --------- Machine On
 Ctrl-Home -- Home All
@@ -37,10 +40,11 @@ with each reload.
 
 To watch the tool data changes and tool usage time
 accrual, use the following command  in a separate
-terminal (source if rip_environment for RIP
-builds):
+terminal (source rip_environment for RIP builds):
 
 $ watch -n 0.2 cat /tmp/db_nonran_file
+or
+$ watch -n 0.2 cat /tmp/db_ran_file
 
 The M parameter in the /tmp/db_nonran_file
 accounts for tool time measured in minutes

configs/sim/axis/db_demo/base.inc

@@ -27,13 +27,15 @@ POSTGUI_HALFILE = db_postgui.hal
 [TRAJ]
 NO_FORCE_HOMING = 1
 
-COORDINATES = XYZ
+# Note:allow all coords for testing
+COORDINATES = XYZABCUVW
 LINEAR_UNITS = inch
 ANGULAR_UNITS = degree
+MAX_ANGULAR_VELOCITY=1000
 
 [KINS]
-JOINTS = 3
-KINEMATICS = trivkins coordinates=XYZ
+JOINTS = 9
+KINEMATICS = trivkins coordinates=XYZABCUVW
 
 [JOINT_0]
 TYPE = LINEAR
@@ -52,3 +54,34 @@ TYPE = LINEAR
 MAX_VELOCITY=1e99
 MAX_ACCELERATION=1e99
 HOME_SEQUENCE=0
+
+[JOINT_3]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0
+[JOINT_4]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0
+[JOINT_5]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0
+[JOINT_6]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0
+[JOINT_7]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0
+[JOINT_8]
+TYPE = LINEAR
+MAX_VELOCITY=1e99
+MAX_ACCELERATION=1e99
+HOME_SEQUENCE=0