Update page 'Search'

Search.md

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+![Search Help Image](https://raw.githubusercontent.com/CS-4820-Library-Project/Libly/master/images/SearchHelp.png)
+
+## Database Functionality
+The search page is connected to an SQLite database that stores all of the report data that has been fetched. Through the interface provided you can create a query as simple or advanced as you need and it will retrieve the relevant data and return it as a TSV file. The queries in this tool are structured in Product of Sum (POS) form, which means that it is a set separated by **and** operators of sets of conditions separated by **or** operators.
+
+## Structuring a query
+
+Select a report type.
+
+Select a year range (start year and end year).
+
+For each condition you must select a **field**, **comparison operator**, and **value**. For example, choosing "database", "LIKE", and "example" would add the condition "database LIKE "example"" to the SQL query sent to the database.
+
+To add a condition at the **or** level, click the appropriate **Add "Or"** button. To add a set of conditions at the **and** level, click the **Add "And"** button.
+
+To remove a condition at the **or** level, click the appropriate **Remove "Or"** button. To remove a set of conditions at the **and** level, click the appropriate **Remove "And"** button.
+
+You can choose whether to open the results, open the folder the results are saved in, both, or neither, by selecting the appropriate radio button.
+
+Once your query is configured press the **Search** button to save the data into a TSV file. 
+
+## Saving your search
+
+**Export Search** lets the user export the search query currently entered into the Search screen to a JSON file. They can then re-use it later by importing it without having to re-enter the query manually.
+
+**Import Search** lets the user load a previously exported search into the program and run or modify it.
+
+## A few notes about the parameters of a condition
+
+The comparison operator **<>** is the "not equal to" operator.
+
+The **LIKE** and **\=** comparison operators have some differences; the most important are that **LIKE** supports the wildcards **\_** (a single character) and **\%** (zero or more characters), and that **LIKE** is case insensitive on the ASCII character set. The same applies for the **<>** and **NOT LIKE** comparison operators.
+
+The type of input allowed for a field is shown above the value parameter box. These can be **Text**, **Integer**, or **Real** (decimal values).
+
+The special comparison operators **IS NULL** and **IS NOT NULL** disable the value parameter. They will check if the value in the database is null (missing), which is different from being 0 or the empty string.
+
+## A few other tips
+
+If you want to do a search for a cost below a number and want to count names (databases/items/platforms/titles) without costs entered as having zero for the cost, you have to add an **or** with the cost as the field and **is null** as the comparison operator.