First commit of code.

New functionality:
- DSMC module:
  - 2D cyl geometry
    - GMSH file format
    - Elastic cross-section for Argon-Argon collisions.
    - Basic boundary conditions: reflection, absorption and axis
      symmetry.

Bugs fixed:

Other comments:
- Still searching for name.

makefile

@@ -0,0 +1,34 @@
+# compiler
+FC := gfortran
+
+TOPDIR =  $(PWD)# top directory
+MODDIR := $(TOPDIR)/mod# module folder
+OBJDIR := $(TOPDIR)/obj# object folder
+SRCDIR := $(TOPDIR)/src# source folder
+JSONDIR := $(TOPDIR)/json-fortran-8.2.0/build
+JSONLIB := $(JSONDIR)/lib/libjsonfortran.a
+JSONINC := $(JSONDIR)/include
+
+INCDIR := 
+INCDIR += $(JSONINC)
+
+# compile flags
+FCFLAGS := -fopenmp -Ofast -J $(MODDIR) -I $(INCDIR) -Wall
+
+#Output file
+OUTPUT = DSMC_Neutrals
+
+export
+
+$(OUTPUT): src.o 
+
+src.o:
+	@mkdir -p $(MODDIR)
+	@mkdir -p $(OBJDIR)
+	$(MAKE) -C src all
+
+clean:
+	rm -f $(OUTPUT)
+	rm -f $(MODDIR)/*.mod
+	rm -f $(OBJDIR)/*.o
+