Clang Format Text Style

Clang-format: ADIOS2 uses the clang-format tool to automatically enforce source code style and formatting rules. There are various ways to integrate the clang-format tool into your IDE / Code Editor depending on if you use Emacs, Vim, Eclipse, KDevelop, Microsoft Visual Studio, etc. that are a bit outside the scope of this document but a quick google search for "integrate clang-format" should point you in the right direction. Main points:
- Lines no longer than 80 characters.
- Always use braces { and }, even for 1 line if blocks.
  - Don't
```
if( number != 1 )
    number = 1;
```
  - Do
```
if( number != 1 )
{
    number = 1;
} 
```
- Use 4 spaces for indentation.
- However, you can always reformat the code manually by running:
```
clang-format -i SourceFile.cpp SourceFile.h
```
Naming: Use meaningful English words, well-known acronyms (MPI, XML, CFD, GMRES, etc.), or well-known short names (Config, Comm, 2D, 3D).
- Examples: initialTime instead of tIni , or work instead of wrk
- One Exception: when redefining long types with the using keyword reasonable mnemonics and short names are allowed, always document scope.
```
// local 2D Vector of doubles  
using std::vector<std::vector<double>> = vDouble2D;
```

Avoid underscores: adds unnecessary length. Reserve it for prefixes of special cases (see class members and lambda functions). Use upper case letters instead.

Don't

std::vector<std::vector<<double>> this_is_my_very_very_long_two_dimensional_vector_name;

std::vector<std::vector<<double>> thisIsMyVeryVeryLongTwoDimensionalVectorName;

Using and typedef keywords: Prefer the keyword using over typedef for readability. Only rename very long complex or custom types, do not rename standard types (int, double, std::vector<double>). Prefer including ADIOSTypes.h as it contains fixed types in the std:: namespace (e.g. uint8_t, uint64_t ).
- Don't
```
typedef std::vector<std::vector<std::map<std::string, double>>> MapIn2DVector; 
```
- Do
```
using std::vector<std::vector<std::map<std::string, double>>> = MapIn2DVector; 
```