Added /apps directory, and moved some problem generators from /src/prob

into it.  This directpory should be used in future to archive problem
generators (and input files) developed for applications.

apps/athinput.turb

@@ -0,0 +1,61 @@
+<comment>
+problem = 3D driven isothermal hydrodynamical turbulence
+author  = J.M. Stone, E.C. Ostriker, & C.F. Gammie, ApJ508, L99
+journal =
+config  = --with-problem=turb --with-gas=hydro --with-eos=isothermal --with-flux=exact --with-integrator=vl --enable-fft
+
+<job>
+problem_id      = Turb       # problem ID: basename of output filenames
+maxout          = 3          # Output blocks number from 1 -> maxout
+num_domains     = 1          # number of Domains in Mesh
+
+
+<output1>
+out_fmt = hst               # History data dump
+dt      = 2.5e-3            # time increment between outputs
+
+<output2>
+out_fmt = vtk
+out     = prim              # HDF-SDS data dump
+dt      = 0.01              # time increment between outputs
+
+<time>
+cour_no         = 0.4       # The Courant, Friedrichs, & Lewy (CFL) Number
+nlim            = 1000000   # cycle limit
+tlim            = 0.5       # time limit
+
+<domain1>
+level           = 0
+Nx1             = 32        # Number of zones in X-direction
+x1min           = 0.0       # minimum value of X
+x1max           = 1.0       # maximum value of X
+bc_ix1          = 4         # inner-I (X) boundary flag
+bc_ox1          = 4         # outer-I (X) boundary flag
+NGrid_x1        = 1
+
+Nx2             = 32        # Number of zones in Y-direction
+x2min           = 0.0       # minimum value of Y
+x2max           = 1.0       # maximum value of Y
+bc_ix2          = 4         # inner-J (Y) boundary flag
+bc_ox2          = 4         # outer-J (Y) boundary flag
+NGrid_x2        = 1
+
+Nx3             = 32        # Number of zones in X3-direction
+x3min           = 0.0       # minimum value of X3
+x3max           = 1.0       # maximum value of X3
+bc_ix3          = 4         # inner-K (Z) boundary flag
+bc_ox3          = 4         # outer-K (Z) boundary flag
+NGrid_x3        = 1
+
+<problem>
+iso_csound      = 1.0       # isothermal sound speed
+gamma           = 1.66667   # gamma = C_p/C_v
+beta            = 0.02      # sets field strength
+dedt            = 1000.0    # energy input rate
+dtdrive         = 0.001     # time interval between drive
+klow            = 0.0       # low k cut-off in spectrum
+khigh           = 16.0      # high k cut-off in spectrum (recommend Nx/2)
+kpeak		= 8.0	    # peak k for G&O spectrum
+expo            = 3.0       # exponent for power-law spectrum
+ispect          = 2         # power-law=1, G&O=2
+idrive          = 0         # driven=0, decaying=1