Qt5 built in qwt (#570)

- qt4->qt5
- in built qt5 6.1.5 because rhel7 is not upto date with qt5, removed findqwt.cmake
- made a fix in qwt lib (qwt_plot_layout.h) to work with 5.15 and lower versions for qrect constr.
- qt5 forms fixed, qt4 many hard coding forms switched to forms including qtabwidget, scrolls etc, fonts moved to forms
 - docking option enabled by default, removed option to disable docking feature from "Mode"
- added qVersionResolve utility functions to handle compatibility before and after qt5.12
- qtplots (ian's code) takes in gain mode enable to set some settings within the class, with proper gain plot ticks
- ensure gain plots have no zooming of z axis in 2d and y axis in 1d
- removed placeholder text in qpalette in main window form as its not supportd until 5.12 (so using qt5.9 designer insted of qt5.15 to cope)
- tab order
Servers:
- fixed some error messages that were empty for fail in funcs (mostly minor as if this error, major issues)

libs/qwt-6.1.5/doc/html/functions_func.js

@@ -0,0 +1,28 @@
+var functions_func =
+[
+    [ "a", "functions_func.html", null ],
+    [ "b", "functions_func_b.html", null ],
+    [ "c", "functions_func_c.html", null ],
+    [ "d", "functions_func_d.html", null ],
+    [ "e", "functions_func_e.html", null ],
+    [ "f", "functions_func_f.html", null ],
+    [ "g", "functions_func_g.html", null ],
+    [ "h", "functions_func_h.html", null ],
+    [ "i", "functions_func_i.html", null ],
+    [ "k", "functions_func_k.html", null ],
+    [ "l", "functions_func_l.html", null ],
+    [ "m", "functions_func_m.html", null ],
+    [ "n", "functions_func_n.html", null ],
+    [ "o", "functions_func_o.html", null ],
+    [ "p", "functions_func_p.html", null ],
+    [ "r", "functions_func_r.html", null ],
+    [ "s", "functions_func_s.html", null ],
+    [ "t", "functions_func_t.html", null ],
+    [ "u", "functions_func_u.html", null ],
+    [ "v", "functions_func_v.html", null ],
+    [ "w", "functions_func_w.html", null ],
+    [ "x", "functions_func_x.html", null ],
+    [ "y", "functions_func_y.html", null ],
+    [ "z", "functions_func_z.html", null ],
+    [ "~", "functions_func_~.html", null ]
+];